Another Classic FWE Built and Run

[larry cottrill]

I got an email yesterday from another fellow who successfully built a 'classic' Short Lady FWE. He happened upon my FWE site pages Friday during his lunch hour, and built it from scratch on Saturday, getting it to run briefly by feeding it acetylene from his torch right at the intake and lighting it from the rear. I am encouraging him to build a good permanent fuel pipe and run it on propane. He sent along three pictures with permission to post them.

He is Mahlon Hull of Scotia, NY, USA. I have suggested that he join the forums, especially if he wants to continue in the pulsejet hobby. I also suggested that he get us some running pictures [after providing a safer fueling setup!] and get on the forum to at least post more details on this build.

He says his camera is cheap, and also felt that his workmanship was not the best [he doesn't have a very small welding torch tip to use], but hey - he got a running engine his first tme out, for a single Saturday's work! And, I don't think his pictures or the workmanship look too bad, either. Have a look ...

L Cottrill

[larry cottrill]

Mahlon sent along the following - very apologetic about the picture, but it's not that bad, and clearly shows the FWE running. Very typical classic FWE heat distribution - all up front in the chamber:

Larry,

Here it is running on Propane.. The picture is
terrible as my camera just doesn't do a good job in
low light. It actually makes it look like a light but
I assure you it's the engine buzzing away.

You can see the starting torch I switched to burning
on top of the vice but no flash from the tailpipe of
the engine. I must have caught it right on a cycle
which is strange at 230 or so cps. I need to get a
spark starter as it gets old trying to get the main
chamber to catch without backfiring the engine to
flame out.

I also tried the acetylene again and it fires way
more powerful but won't stay running, it needs no
starting air. The propane took me about two hours to
learn the right fuel air combo to get it to take hold
and run. My gas valve is not fine enough for the
operation. I'll have to switch to a needle type.

I'll try again in a few days and see if I can't get a
video since that camera works much better.

Mahlon

[larry cottrill]

I asked Mahlon to send some personal info, and he sent this reply, along with a nice photo of a typical day on the job:

Larry,

Went and started it three times in just under 40
minutes today (that includes the 5 minutes or so I let
it run per event). I've got the technique down pretty
good - to suck the flame into the combustion chamber,
throttle up slightly, back off the air (not pressure
but distance), increase the gas flow then air flow to
resonance. I'm also able to tune it up for max power
now as I've learned how to micro adjust the valve I'm
using. The pitch (CPS) goes up as I get the mixture
just right, it gets kind of crabby sounding if I get
too rich and slows down if I get it lean. Seems to be
throttle capable over a small range.

So, I'm 43 years old, a Physics Major, Washington
State University, Employed by the New York Air
National Guard, LC-130 Pilot. We fly the Antarctic
missions for the National Science Foundation. I love
science and scientific things like the Short Lady....

I've attached a picture of the rockets I get to
use/play with on a professional level. Each one
Produces 1,000 lbs of thrust. So that's 8,000 lbs of
pure rocket blast you're looking at. Kind of fun when
it's bolted to the airplane.

Your web site and invention has been the talk of the
pilot shop for the last two days. We're impressed...

Mahlon

[hagent]

There was a Darwin award given out a number of years ago to a person who strapped one of those rockets (JATO) to his car.

A State trooper came upon the reckage of what he thought was a plane that slammed into the side of a mountain 100 or so feet off the roadway out in some desert.

If I find the award text I'll post it... I don't think anyone actually proved it happened though.

Cheers.

[larry cottrill]

Hagent -

Sorry, but that one is a known hoax. There was a great story on the 'net someplace about how that story supposedly came about, but I don't know if I could find it anymore. It was a wonderful tale of a few young teenage boys who made a rocket sled out of an old mining car and test fired it. Seemed technically feasible [one kid's dad was a salvage merchant dealing in USAF surplus] and it was a great read.

L Cottrill

[hagent]

Dang!

It was such a great story. I wish it was true. Except for the dead guy of course.

[mk]

So did Mahlon only use the torch to start his engine?
I wonder, because he said something to get his spark done.

If so, did he start by igniting the gas at the inlet, the exhaust or only by heating a spot at the comb. chamber?

Would be nice if Mahlon would join the forum group.


Argh! These English/American keyboards are different to the German ones in some nasty details...